Strong



(No Model.) J. B. RMSTRONG.

SPRING.

No. 267,817. Patented N0v.-14, 1882.

EWGTIZZOTK $9 M)" kw flip/ ag #dm 7/ N. PETERS Fhclo-LilhogmphuWashmglon, n. c.

NITED STATES JOHN B. ARMSTRONG, OF GUELPH, ONTARIO, CANADA.

SPRING.

SPECIFICATION forming'part of Letters Patent No. 267,317, dated November14, 1882.

Application filed March 9, 1882.

To all whom it may concern;

Be it known that I, JOHN BELMER ARM- STRONG, a subject of the Queen ofGreat Britain, residing at the city of Guelph, in the county ofWellington, in the Province of ()ntario, Canada, have invented certainnew and useful Improvements in Springs, of which the following is aspecification.

My invention relates more particularly to that class of springs known assingle-plate springs, and it consists of the peculiar construction,arrangement, and combination of parts, as more fully hereinafterdescribed and claimed. I

Figure 1 is a side elevation of my improved single-plate ellipticspring. Fig. 2 is an enlarged detail, showing the center portion of thespring, with the teat punched out of the solid stock. Figs. 3 and 4 areenlarged details of a portion of the plate, showing the formation of theholes. Fig. 5 illustrates the means for obtaining the independent bossor thimble, the construction there shown being made the subject-matterof a separate application.

After m any years of experience in the manufacture of single-platesprings, I have at last discovered that in order to secure the greatestease of motion and at the same time have the strain evenly distributedthroughout the plate it is necessary to graduate the thickness of thespring on a taper of twelve sixtyfourths of an inch to the foot. I haveexperimented for some years, and have at last arrived at this taper asbeing the only one which will give the desired elasticity and ease ofmotion to the spring. In single-plate springs lightness is one of theobjects aimed at. The plates are made so thin that the removal of anyportion of the material is calculated to weaken the spring at thatparticular point. To avoid this, and at the same time enable me toobtain either a center teat or holes for the center bolts, I in thefirst instance punch the stock of the spring, so that it will protrudeand form a teat, A, on the inside or outside face of the plate as may berequired, but without breaking the material'or in any other wayweakening the spring at that point.

In order to have a hole for the center bolts, without weakening theplate at the point pierced, I use a punch and punch-block, so shapedthat it will force the skin of the plate (No model.)

through the hole, forming either a concave hole, as shown in Fig. 4, ora straighter hole, as shown in Fig. 3. This I accomplish by means of apointed drill or punch which will neither take away any portion of themetal nor materially rupture the fiber nor-injure the grain. By slowpunching the metal immediately surrounding the point of the punch isdeflected downward and outward to form a separate boss at approximateright angles to the plane of the spring, as it is confined in the hollowblock, where it is forced.

A sleeve or thimble being formed, when the spring is punched as shown inFig. 3, by the outer skin of the plate protruding beyond the surface ofthe face, or when punched as shown in Fig. 4 a convex projection isformed on the outer side and a concave indentation'on the inner side ofthe spring around the hole. (Jonsequently in either case the point inthe plate through which the hole is made is, if anything, stronger,while the projection formed on the face of the plate forms a teat whichassists in securing the spring on its seat. In order to secure the endsof an elliptic spring rigidly together, the ends are straightened on aline with thelongitudinal center of the spring, and the inside faces ofthe ends thus straightened are brought into contact with each other, andheld rigidly together by a bolt, rivet, or

clamping device, or only separated by a light piece of packing. By thusclamping the ends of the plates rigidly together there can be nomovement in the joints, and consequently not only is all noiseprevented, but also the wear caused by the rubbing of the platestogether is obviated.

I am aware of Patents Nos. 68,217, 100,626, 151,881, and 237,849, and Ido not claim the construction shown in either.

What I claim is- A single-plate elliptic spring having holes re-enforcedby a boss or thimhle to receive the fastening-bolts, said holes being sopunched that the grain of the stock at the hole is turned at or about atright angles to the spring, whereby the spring is strengthened at theholes, substantially as described.

J. B. ARMSTRONG.

Witnesses WM. E. SLAKER, H. ARMSTRONG.

